Device for tying the ends of yarns



Nov. 12, 1968 A. ALTENWEGER v3,410,590

DEVICE FOR TYING THE ENDS OF YARNS Filed April 10, 1967 United States Patent 3,410,596 DEVICE FOR TYING THE ENDS 0F YARNS Alois Altenweger, Uster, Switzerland, assignor to Zeliweger Ltd., Uster, Switzerland Filed Apr. 10, 1967, Ser. No. 629,775 Claims priority, application Switzerland, Apr. 15, 1966, 5,573/ 66 7 Claims. (Cl. 28912) ABSTRACT OF THE DISCLOSURE A device for tying the ends of yarns having a stationary mandrel and a yarn gripper positioned adjacent the end of said mandrel and mounted for rotation thereabout wherein a cam wheel rotated relative to the gripper provides a cam track within which a follower connected to said gripper rides for effecting movement of said gripper toward said mandrel.

Background of the invention Many different mechanical devices have been utilized for the tying of threads and filaments. One of the major classes of thread tying devices relies for its action upon a sleeve arrangement in the form of a mandral around which the thread loops are formed, which mandrel surrounds a retractable reciprocating hook. After the loop formation on the mandrel, the retractable hook draws the ends of the threads into the interior of the mandrel sleeve so that on stripping the loops over the free end of the hook the desired knot is formed.

For the desired loop formation, the mandrel and the clamps holding the ends of the threads must rotate relative to each other and this may be accomplished either by the rotation of the mandrel sleeve itself, which is provided with a hook operatively connected to the sleeve, or by the rotation of the clamp holding the thread ends above the stationary sleeve. For the formation of loops, the length of thread required is provided in each case by permitting the thread ends fictionally engaged by the thread clamp to slide therein. The thread clamp is so designed that it is held in closed position, for example, by means of a spring and may be opened either by the action of the thread itself or it may be so designed as to be held in closed position by the action of a spring and opened by suitable means of the tying machine. The latter design and arrangement of the thread clamp has usually served heretofore only to enable the threads to be inserted more easily since the threads, in each instance, after the completion of the knot-tying step are caused to slide free of the thread clamp.

In the device for tying the ends of yarns in accordance with this invention, the loops required for a given knot are formed by means of a stationary mandrel in combination with a yarn gripper which both rotates around the mandrel and makes an axial movement with respect thereto. Since the ends of the yarn have to be wound on the mandrel during loop formation, they have to be pulled through the yarn gripper, which follows a circular path with the mandrel at the center. However, sensitive yarns are damaged when they are pulled through the gripper; for example, the necessity to pull yarns through the gripper is a particular disadvantage to knot and loop yarns because they can be stretched, which adversely affects the function of the tying components. Another disadvantage of pulling the yarns through the gripper is that the gripper itself is subject to considerable wear at the gripping point.

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Brief description of the invention In the device as proposed in accordance with the present invention, one exemplary embodiment of which is disclosed herein, the yarn gripper, during its movements around the axis of the mandrel and parallel thereto, as required for loop formation, approaches the said axis in such a way that, at each stage of the loop formation, that part of the mandrel onto which the yarns are wound substantially forms the evolute of the path followed by the yarn gripper. As a result, the ends of the yarn no longer are pulled through the yarn gripper, since the feeding of yarn to the mandrel during the formation of the knot is provided during this operation by progressive movement of the yarn gripper in the direction of the mandrel. Thus, not only is possible damage to the yarn itself as a result of the previous pulling of the yarn through the gripper eliminated; but also, the problem of wear to the gripper at the gripping point thereof is also substantially eliminated.

It is, therefore, an object of the present invention to provide a device for tying the ends of yarns which altogether eliminates, or otherwise substantially avoids, all of the aforementioned disadvantages inherent in known devices of a similar nature.

It is another object of the present invention to provide a device for tying the ends of yarns which eliminates the need during knot formation for effecting relative movement between the yarn and the yarn gripper.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description thereof when taken in conjunction with the accompanying drawing wherein the sole figure is a perspective view, partly in section, of the knot tying device of this invention.

Specific description of the invention As illustrated in the sole figure, a device for tying the ends of yarns is accommodated in a housing 1 of any general configuration. It is driven by a motor (not shown) which rotates a main shaft 5 by way of an intermediate shaft 2 and a pair of spur wheels 3 and 4. The main shaft 5 makes one revolution for each tying cycle. A mandrel 6 is fixed to the housing 1 and is of conventional design incorporating conventional threading and ejecting needs (not shown).

The yarn ends to be tied together are taken up, in the known manner, by a rotatable yarn gripper 7 and guided around the mandrel 6 in order to form the loops required for tying a knot. The yarn gripper 7 is kept closed under the pressure of a compression spring 8 and is pivotally mounted on a pin 9, which in turn is anchored in a collet 10. The collet 10 is slotted and connected firmly by clamping to a sleeve 12 by means of set screws 11. A rearward extension 13 of the yarn gripper 7 has a shoulder 14 which engages around a roller lever 15 which is also rotatably mounted on the pin 9. A spring bolt 16 fixed to the roller lever 15 projects through the shoulder 14, and in conjunction with a compression spring 17, presses it against the roller lever 15 so that the yarn gripper 7 moves into the position illustrated. The end of the roller lever 15 carries a roller 19 which travels in a cam track around a cam wheel 20.

The cam wheel 20 is rotatably mounted on the sleeve 12 and has a toothed rim so that it can be rotated by a pinion 21 mounted on the intermediate shaft 2. The sleeve 12 also has a spur wheel 22 which is driven by a pinion 23 mounted on a shaft 24, which is rotated by a pinion 25 meshing with the gearwheel 4. The sleeve 12 is-provided with a groove 26 in which a fork 27 is engaged. The fork 27 is fixed to a bolt 28 which is resiliently pressed against the cam disc 30 under the action of a compression spring 29. The cam disc 30 is mounted on the main shaft 5, and, during each tying cycle, imparts an axial movement to the sleeve 12 and hence to the yarn gripper 7 by way of the bolt 28 and the fork 27. The number of teeth in each of the gearwheels required to produce a conventional roll-type knot, should be fixed in such a way that, for each revolution of the main shaft 5, the sleeve 12, and hence the yarn gripper 7, complete three revolutions about the axis of the stationary mandrel 6 while the cam wheel completes only two. Accordingly, each time the main shaft 5 completes a revolution, the yarn gripper 7 is displaced by one revolution about the cam disc 20.

The device operates as follows:

For each revolution of the main shaft, the yarn gripper 7 completes three full revolutions around the mandrel 6, during which time the loops are formed in known manner on the mandrel 6. For this purpose, the yarn gripper 7 has to be displaced parallel to the axis of the mandrel 6, in known manner, which is effected by the cam disc in the manner referred to above. In addition, during loop formation, for the purpose of providing yarn for the loops on the mandrel without pulling the yarn through the gripper 7, the yarn gripper 7 is displaced in accordance with the invention towards the axis of the mandrel 6 by the cam Wheel 20. The cam wheel 20 is provided with a cam track which is designed in such a way that, at each stage of loop formation, the yarn gripper is moved by the roller 19 riding in the cam track so that part of the mandrel onto which the yarns are wound forms the evolute of the path followed by the yarn gripper. With the cam wheel designed in this way, the yarns do not have to be pulled through the yarn gripper 7, since the radial movement of the gripper provides the required yarn for the loops. Accordingly, the pressure exerted by the spring 8 can be adjusted to such a level that the ends of the yarn are surely but safely held in the gripper 7.

Due to inevitable inaccuracies in the manufacture of the individual components and particularly in the design of the mandrel 6, the yarn gripper may not move sufiiciently close to the mandrel 6 during loop formation. For this reason, the yarn gripper 7 is pivotally mounted on roller lever 15 so that it can rotate with its rearward extension 13 relative to the roller lever 15 against the pressure of the spring 17 in exact dependence upon the length of yarn wound onto the mandrel 6.

I have shown and described one embodiment in accordance with the present invention. It is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art and I, therefore, do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

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1. In a device for tying the ends of yarns including a stationary mandrel, a sleeve mounted for rotation on said mandrel, a yarn gripper positioned adjacent the end of said mandrel and mounted on said sleeve for rotation therewith about said mandrel wherein the improvement comprises means for controlling the position of said gripper with respect to said mandrel during its movement therearound to approach said mandrel so that the part of the mandrel onto which the yarns are wound substantially forms the evolute of the path followed by the yarn gripper.

2. The device defined in claim 1 wherein said means includes a cam wheel having a cam track mounted for rotation with respect to said sleeve and said mandrel, and a follower member positioned in said cam track and connected to said yarn gripper for positioning said gripper in accordance with the shape of said cam track, and drive means for rotating said yarn gripper at a speed which is an integral multiple of the rotational speed of said cam wheel.

3. The device defined in claim 2 wherein said follower member is resiliently, pivotally connected to said gripper.

4. In a device for tying the ends of yarns including a stationary mandrel, a sleeve mounted for rotation on said mandrel, a yarn gripper positioned adjacent the end of said mandrel and mounted on said sleeve for rotation therewith about said mandrel, a cam wheel having a cam track mounted for rotation on said sleeve, a follower member positioned in said cam track and connected to said yarn gripper for effecting movement of said gripper toward said mandrel in accordance with the shape of said cam track, and means for driving said sleeve and said cam wheel in rotation.

5. The device defined in claim 4 wherein said cam track is shaped to guide said gripper so that the part of the mandrel on which the yarns are wound substantially forms the evolute of the path followed by the yarn gripper.

6. The device defined in claim 4 wherein said drive means includes gear means rotating said cam wheel with respect to said sleeve to the extent that said sleeve effects one complete revolution with respect to said sleeve during a complete tying operation.

7. The device defined in claim 4 wherein said follower member is resiliently, pivotally connected to said gripper to insure without limiting movement of said gripper toward said mandrel under control of said cam track.

References Cited UNITED STATES PATENTS 238,327 3/1881 Augspurger 289-12 1,099,128 6/1914 Poege 289-12 2,879,095 3/1959 Altenweger 289-12 X 2,977,144 3/1961 Gegenschatz 289-12 LOUIS K. RIMRODT, Primary Examiner. 

